Software/documentation for the LSI-11 inside a Bridgeport Series II CNC milling machine?

Jim Beacon jim at
Thu Nov 19 19:34:10 CST 2009

From: "Ethan Dicks" <ethan.dicks at>

> Hi, All,
> I was helping someone in town with some motor issues on their
> circa-1980 Bridgeport CNC mill for which they fortunately have many
> original docs.  I was tremendously surprised to find that there's an
> LSI-11 in the heart of the CNC cabinet.  The docs have schematics,
> register maps, etc., and even instructions for how to use the
> Bridgeport punched-tape-loadable diagnostics.  Fortunately, this unit
> has the optional punched-tape reader.  Unfortunately, it has no tapes.
> I've done some cursory looking around and little is leaping out at me
> (except frequent mentions of folks who have upgraded away from the
> original CNC package).  I'm wondering if anyone on the list knows
> where to pick up images of the diagnostic software for this thing.
> Thanks for any tips or hints.
> -ethan
Hi Ethan,

you may want to try in either the Bridgeport or the Antique Machinery 
sections of Practical Machinist:


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